(R8C/Tiny) Why does the value of DPSIFR1 differs from user's manual hardware?

Question:

Why does the initial value of register DPSIFR1 sometimes differ from that which is shown in the microcontroller's user's manual: hardware?

Answer:

When a cancellation source is generated before DPSIFRi is read, the read value may differ from the value after reset that is shown in the user's manual: hardware.
The flag in deep standby interrupt flag register i (DPSIFRi; i varies depending on the product) is set to 1 (canceling deep software standby mode is enabled) when a cancellation source is generated, even in modes other than deep software standby mode and even when the bit in deep standby interrupt enable register i (DPSIERi) is 0 (canceling deep software standby mode is disabled).